Executive Pro – Display second sub-menu of the last top level navigation item to the right

/*
.genesis-nav-menu = ul wrapping all menu items
li = top level menu items
li:last-child = last top level menu item
.sub-menu = ul of the second level menu items
.sub-menu = ul of the third level menu items
*/

.genesis-nav-menu li:last-child .sub-menu .sub-menu {
    right: 100%;
}